Aside from the obvious elephant in the Bostonian room, not much. There was some interesting news about a skin tape thing inspired by the stuff that tapeworms use to cling to tissue, and three potential candidates for habitable planets that the Kepler space telescope discovered (I only think of one of them is truly promising – the other two are probably super-Venus planets).

I’ve been toying with an idea for an alternate gay gene hypothesis. The logic goes as follows:

Suppose you’re a male human living in a small band, roughly in main evolutionary environment. Suppose you discover that the girl you want doesn’t feel that way about you. Suppose you decide that your status and attractiveness are not high enough and you’re afraid you’ll never be able to get a desirable woman. What’s the right response, i.e. one that instinct might cause you to prefer? I can’t be sure of course, but a reasonable guess is that your instinct would be to try harder. Be more aggressive. Get more attention. Take more risks. Be impressive. If it works, you become more attractive. If it fails, you took some extra risks but there’s a good chance you’re not much worse off than when you started.

What happens when your descendants start living in a hierarchical, agricultural society? For the part, they will be commoners. However, many of the most attractive women will be born into the upper classes, and most of the other attractive women will quickly get married off into the upper classes. What happens when they respond by trying harder to get the girls they want? If they act aggressively toward their social betters, the usual result will be that they are killed. If they cause enough trouble, maybe their relatives will be killed, too. A better strategy under the circumstances would be to get used to settling for less and gradually try to claw their way up the social ladder.

Suddenly, the “try harder” genes, once crucial to mating success, are an enormous liability. Any mutation that ameliorates that problem is suddenly valuable. What if a mutation arose that altered the development of sexuality in ways that made male sexual attraction more flexible: essentially a gene for bisexuality. The men with this gene would be less likely to get their hearts set on an attractive woman, and would be more content to direct their sexual energies toward a local man. This would enable them to bide time to marry later, or feel more content being married to a woman they don’t find very attractive, without having to become asexual. The most successful version of this trait might include a mechanism to gauge the man’s status during childhood and inculcate more or less bisexuality on that basis.

In the most recent several generations, the descendants of these men find themselves in a new environment again. The social stratification that endangered their ancestors is much less draconian. At the same time, the childhood environment is different from anything their ancestors had experienced. What if the novel developmental environment caused some men with the “bisexuality” gene to develop as if their social status was “off-the-charts low”? The resulting phenotype might be exclusive homosexuality. Which aspects of the modern childhood environment might fool the brain into thinking the individual’s social status is extremely low? There are a many ways in which our childhoods today are different from the rest of human history, both behavioral and chemical, so there are many possibilities for the cause of status misassessment. One possibility that comes to mind is gender equality. The brain may gauge status partly on the basis of “how deferential are women toward me?” which makes sense in a medieval, hierarchical society, but modern gender egalitarian women might come across as “0% deferential”.

The implication of this thought experiment is that bisexuality was once adaptive but is probably not adaptive any more, while exclusive homosexuality is definitely maladaptive. Therefore, we would expect homosexuality to disappear from the population quickly over the next several generations.

Ironically, if this speculation were somehow someday proven to be true, the newspaper headline about it could easily be: “Feminism causes homosexuality!” — a misleading but sensational summary.

Toby Chamberlain

Your theory would make more sense if homosexually was a recent development found only in humans and only in post-agricultural societies. On the contrary homosexual behaviour has been recorded in over a thousand different animal species across a wide range of social structures. One can only assume it has been a part of life on earth for hundreds of millions of years so it’s unlikely that a “cause” will be found in the last 10,000 years of human evolution.

toto

Death of Francois Jacob, co-discoverer of gene regulation and Resistance hero.

Some people seem to have been born just to make your life seem even more inadequate and insignificant than you thought it was.

Too busy to scratch myself, but I might have something to talk about later which some might find interesting – a civil engineering project that on the face of it doesn’t work, but it does work, and everyone benefits.

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Gene Expression

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About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com